Impact-tool.



PATENTED MAR. 13'|` 1906.

' G. L. BADGBR.

IMPACT Tool.. APPLIOATION FILED IBB. 8, 19706.

haust b the latter as ordinarily arranged, the fluid proper working GEORGE L. BADGER, OF QUINCXCJ ASSACHUSETTS.

IMPACT-TOOL.

To all whom it may concer-1t:

Be it known that I, GEORGE L. Banana, o Quincy, in the county of Norfolk and State of Massachusetts, have invented certain new and useful Im rovements in Impact-Tools,

of which the fo lowing is a s ecication.

The principal features o the present invention relate to the novel valve mechanism for controlling the movements of the piston.

The greatest difficulty with fluid-actuated valves as heretofore constructed has been that after a short period of service the fluid will leak by the bearing-surfaces ofthe valve and create a pressure on the controlling-pressure surfaces which interferes with the proper operation of the valve.

It is'the object of the novel valve consti tuting this feature of my invention to prevent the fluid that mayleak past the bearingsurfaces from creati? a pressure on the controlling-pressure s aces of the valve, the fluid passing into the exhaust and not interi'ering with the ro er o eration of the valve, whereby the l' e ci) the Elatter is greatly prolon ed.

,i en {luid-actuated valves are controlled By the movements of the piston and are actuated b means of liuid supplied to and exfrom ports and passages controlled w 'ch leaks ast the piston when the latter becomes slig tly worn also interferes with the pro er operation of the valve. v Y It is t e object constituting the second feature of my invention to prevent the fluid leaking past the piston from interfering with the roper operation of the valve, whereby the ife of the former is greatly prolonged.

In the, practical operationof` motive iiuid past the valve and iston interferes with the pro er working o the tool before the waste of uid becomes great enough to be taken into account.

. It will be understood that while a larger amount of motive duid be required to op, crate a tool when art ci the iiuid supplied escapes past the va ve and piston when constructed in accordance with my invention the escaping fluid does lnot interfere with the 'ofthetool .Y n v Another feature relates to an auxiliary eX- haustort in the valverblock controlled by the va ve, whereby additionalA means is ro,

vided for exhaustmthe motive ilu'id om the forward end of t e' piston-chamber.

Specification of Lettera Patent. Application Bled February 8,1905. Serial No. 244,765.

the passage leadin neu'rn'atictools as ordinarily constructed t e leak of' Patented March. 13, 1906.

1t is desirable in impact-tools that the ex haust from the forward side of the piston Ashall be'as free as possible in order that the s eed of the piston will not be retarded, so t at the force of the blow delivered by the latter on the working tool will not be cushioned by the back pressure ci the exhaust. It is a so desirable that the amount of motive fluid admitted to the forward end of the piston-chamber shall be comparatively limited,

wardly with great force.

y l rovide the passage leadin from the valve-block to the forward end o the istonchamber, through which the motive uid is admitted and exhausted from the forward side of the piston, with two ports controlled 'by the valve. One of these `ports serves to admit and exhaust the motive iluid to and from the forward end of the iston and is of lsuch capacity as to drive tie iston reariwardlyat the required speed. T e second or :auxiliary port, which is of much greater capacit serves as additional means to exhaust lwhen the valve is in one position and when the valve is moved in an opposite direction to admit an additional amount of fluid to mainvtain a pressure on the lar er area of the valve.V This lastifeature of itsel however, is not o-` i eat importance, as I provide other means or maintainin a pressure on the ,larger area lof the valve urin the rearward stroke of thepiston, as will e hereinafter described; butA as the larger area of the valve is con- Vnected by means of said auxilia port and to the forwar end of the piston-chamber w 'en the latter is ened to the atmosphere by a port uncover by the piston when vnear the end of its rearward stroke said auxiliary port and passage furnishes additional means of larigre capacity for quickly relievingthe pressure om the larger area o the valve, whereby the latter can be moved uickly by the motive duid that is constant y admitted to the differential press suresurfaces of the valve, as Will be hereinafter described.

In the novel valve mechanism of this invention'the valve consists of a tubular shell of diierent diameters provided with an annular groove located between the large and small diameters or bearing-surfaces of the shell. The motive fluid is constantly admitted to said annular oove and acting on the differential area of t e Walls thereof tends to 'the uid from'the forward end of the piston` so that the piston will not be driven rear- ICO sis

press the valve always in one direction. The shell is provided with another annular groove located in the larger diameter, said groove being connected with the interior of the shell by aseries of holes or ports, the interior surface of the valve being always open to the atmosphere by an exhaustassage in Conner;- tion with one end of' the va ve-ehamber. The valve is preferably elosed at one end, as it can thus be Ymade shorter and ,rovides a larger pressure-surface at one ent but this Vconstruction isnot essential to the broader scope of my invention, as will be apparent from the description hereinafter given and from the terms of' my respective claims. It follows from the eonstruetion of the valve and arrangement of the ports in the valvebloel'i that the motive fluid which is admitted to the annular groove between the large and small learing-surfaees of the valve to press the latter in one direetion and from which groove the motive fluid is alternately supplied to opposite endsl ol' the iston-ehamber that said fluid eannot reaeh t ie pressure-surfaees ofl the valve. The fluid that may leak or esenpe past the bearing-surfaces of the valve eannot ereate a pressureon the pressure--surfat-es of the 'n|\'e. As in the easeof the larger hearing-surf'aee the fluid will enter the annular groove therein and pass through the holesl eormeet ing seid groove with the interior ofthe valve, whit-h, as before stated, is alwa) s open to the atmosphere. [n the ease ofthe lsmaller bearing-surf'aee the fluid escaping past the same cannot ereafe tt pressure on that end of' the valve` as said end is always open to the atmosphere. The valve is provided with a pressure-surfaee of larger area than the efl'eetive area of said diflerential pres-sure-surfaees, the motive fluid being intermittently admitted to said pressure-sur- I'aee of larger area to move the valve in an opposite direction. lu the preferred oonstruetion where one end of the valve is closed the intermittent fluitl-pressure is admitted to the large elosed end of the valve. In a modified eonstruef ion ofthe valve the large diameter is provided with a small projet-ting end whieh lits into a bore in the plate which Closes the forward end of the valve-ebamber, both ends of' the valve in this instanee being open to the atmosphere, the intermittent fluidpressure being admitted to the' annular shoulder formed b v the large diameter of the valve and said projecting end. To prevent the motive fluid that may escape. past the piston or from other causes to the larger area of the valve from all'et'tting or interfering with the movement ofl the latter, I provide the passage leading from the larger area of the valve to the psttm-t-.hamlwr with an auxiliary port eoutrolled b v the piston, said port being loeated near the forward end ofl the pistonehamber and bemgelosed by the pistou when the latter approat-.hes the forward end ol' itsl ismael stroke. The assage from the large area of the valve to tlie piston-chamber is provided with an admission-port con trolled by the piston and adapted to aetuate the valve in one direction, as is usual in tools of this olass provided with differential valves. An exhaustport is opened by the piston near the end of its rearward stroke to allow the valve to move in an opposite direction. The auxiliary port when uncovered by the piston is alternately placed in eonnnunioatlon with the supply of motive fluid and with the atmosphere by means of the valve-controlled passage leading to the forward end ofthe pistonehamber through which the fluid is admitted and exhausted from the forward end of the piston by the shifting of the valve, whereby an additional amount oi fluid is supplied to the large area of the valve im' one stroke of the piston and the fluid exhausted from said area of the valve on the opposite stroke of the iston. lt will be understood that the fluidpadmitted and exhausted by means of the said auxiliary port to and from the large area oi the valve oeeurs when the piston is moving in an opposite direction from that in p which it is moving when the fluid is admitted and exhausted, respeetively, by the beforementioned admission and exhaust ports to and from the large area of ,the valve to shift the valve. The. auxiliary port is Closed by the piston before the admission-portie opened to admit fluid to the large area of the valve to shift the latter, so that the fluid cannot eseape through the auxiliary port7 and the latter can be of large ea` iaeity. 1t results from this eonstruetion and arrangement that the motive fluid is admitted to the large area of the valve during the greater part of the stroke of the piston in one direotion and exhausted from said area of the valve duringr the greater part of the op insite stroke of' they piston, whereby the vaiie is positively held in its respective position during,r the stroke of" the piston in eaeh direction.

In tools of this elass as ordinarily constructed the motive fluid is admitted to the larger pressure-surface of the valve when the piston is near one end of its stroketo shift the valve and the fluid exhausted from said surf'uee when the piston is near the opposite end ot' its stroke to allow the enlistantlv-acting pressure on the smaller area to shift the valve m an opposite direetion. luring the intermediate travel of'the piston the admission and exhaust ports to the larger pressure-surlate of the valve 'are elosed by the pistou. when the fluid has been exhausted from the larger m'essure-surfaee of the valve. to shift the latter' and the piston in its travel has elosed the exhaust-port from the valve, iF the motive fluid reaehes or eseapes to said lsurfaee ofI the valve it will overeome the eonstantfy-aet ing pressure on the smaller area of the valve and the latter will be moved at the ICO i valve; but I no not y means by which the motive fluid is conducted wrong time and cushion the blow of the piston if the latter is on its forward stroke or shorten the stroke 'if the piston isy moving rearwardly. In some tools of this class it has been sought to avoid this diflieulty by providing an exhaust port or ports located near the forward end of the piston-chamberV Vand admit the motive fluid to the forward side of the piston for a small part of its rearward stroke and depend on the momentum of the piston to carry it to the rear end of the piston-chamber; but since in order to cnt oil' the sup ly of fluid to the forward side of the piston t e valve is shifted to admit the motive fluid to the rear end of the piston it results that the latter will travel rearwardly but a comparatively short distance after the motive fluid is admitted to the rear end of the giron-chamber. By providing a passage m the lar er areaof t e valve to the pistonchamber, w 'ch is always open to the latter, except when the piston is near one end of its stroke, the motive fluid that-may escape past the iston or between the joints of the valvebloc and cylinder or between the latte;l and the outer jacket to the passage leading to the large area of the valve, 1s prevented from creating a ressure on thlatter when the piston is trave ing in a predetermined direction, and l am enab ed to overcome a serious objection to vthe practical operation of tools of this character. c I refer to provide a passage leading from t e larger area of the valve to the piston-chamber with an auxiliary portie addition tothe admission-port by which the motive fluid is admitted to the large area of the valve; but it will be understood that a separate passage for each of said ports lead- A ing from the larger area of the valve to the piston-chamber may be employed instead of a Isingle passage having two portsn The term auxilia port" 1s employed herein and in the claims to means of which an additional amount of movtive fluid is supplied tolthe'valve or which provides additional means for exhausting the fluid from the larger area of the valve.'

'Anotherfeature fof my invention relates to a novel form of throttle-valve for controlling the initial admission of motive fluid to the tool. Said valve is provided with a as inghandle removabl secured to the stem of thevvalve, said 'han e and stem in the resent instance having a pass e' through 'wgaioh the motive fluid is supplie to the throttleto the throttle-valve. Y The stem of the throt-Y tlc-valve is preferably integral with the lati ter, but such a construction xs not tialto the broader scope of my invention, asfwilljbe apparent from the description f, f given and from the terms of my-ripct? con:

claims. The throttle -valvais of shape, the smaller endiiaein'g towa'dthe rear l mall designate a port byf imit -Y myself to the Y end of the tool, and is provided with a rear Wardly-pro'ecting stem of smaller diameter, said stem aving a grasping-handle removably secured thereto for ho ding the tool to the work. A stalling-box engages the stem and can be adjusted to prevent the motive fluid from escaping from around the rear end of the stem, and means is provided for norhoding the throttle-valve in a rearwar ly or seated position to cut off the supply of fluid to the tool. Said means also serves to hold the tin'ottlevalve in engagement with the stem when the latter is notintegral therewith. In tools of this class as ordinarly constructed the throttle-valve fits pluglike into its socket or seat and there'is no means for taking u the Wear between the valve and its seat. en the valve becomes slightly worn, the motive fluid escapes past the bearin -surfaces of the valve to the tool and aroun the rear end ofthe valve to the atrnos here. With my novel form of throttie-va ve there is practically no sliding movement of the valve on its seat and any wear that ma occur is automatically taken up h the longitudinal movementrof thelvalve Wit relation to its seat and the body of the tool. The valve itself froms a stop for the rear'- Wardv movement of the latter and no other means are required to prevent rearward dislacement of the valve with relation to the body of the tool. When the throttle-valve is held in its forward or unseated position by means of its stemand the grasp handle,' the body of the tool may be rotate with relation to said valve without causing any wear between the face of thelatter and its seat, since the valve isnot at such time in contact with its seat. When tools of this character are employed for drilling holes in Vsto e or forotlier purposes where it is essentia that the Working tool be rotated with relation to the work; saidvsforlrinV toolmay be engaged by the body of the too and the latter be rqtatedwithrelation to the throttlevalve, grasping-handle, and source of Huidressure suply to rotate the working tool.l

Idv novel t ottle-valve is especially well apted for a tool wherein the kworking tool is rotated by rotating thefbody. of the tool .with relation to said valve andthe source of fluid-pressure su ply; but this feature is not essential and ot working' tool ma be employed.' Y

My invention rther consists of novel detal'lsof construction all as will be hereinafter emily delicately c aims. t i f In the drawings, 1 is a longitudinal central section of aV pneumatic im -act-tool illustrating the invention, showing t e valve and pointed out in the 'l and hammer in their forwardpesxtion. Fig.

2 is accenti-al scctionon line 2f2 of F' 4. Fisasection through the valve and v veloc taken on the same line-MEQ.;15show-v means for rotating the' ing the valve in its rearward position. Fig. 4 is a cross-section on line 4 4 of F ig; 1. Fig. 5 is a cross-section on line 5 5 of *ig. 1. Fig. 6 is a cross-section on line 6 6 of Fig. 1. F ig. 7 is a cross-section on line 7 7 of Fig. 1. Fig. 8 is a cross-.section on line 8 8 of Fig. 1. Fig. 9 is a cross-section on line 9 9 of Fig. 1.

The tool comprises a cyllinder B; an outer casing B; a piston (or ammer) G, which moves in said cylinder; a valve-block I at the upper or rear end of the cylinder and formed wibli a' Ychamber I; a va ve J located and movin in said ohamber; an upper head or plate for the cylinder; a grasping-handle 0, removably connected to a stem N', that projects. from a throttle-valve N, said handle and stem having a passage connecting with the source of uid-pressure which operates the tool; a forward head C, which receives the drill or working tool, and a turning-liandle F secured to the cylinder and forward head for the purpose of rotating the working tool; a retaining-head M, having a flange which is engaged ly an internal shoulder of a member or sleeve which. is in threaded engagement with the cylinder; a split clamp L, which is ada ited to grip the cylinder and sleeve; a stu `ngbox l) in threaded engagement with the retaining-head, and a jam-nut Q to prevent the stuffing-box from unserewing.

The throttle-valve N is mounted in the retaining-head M in such manner as to be movable both longitudinally and rotatably. 'lhe retaining-head M is provided with a longitudinal bore of dilierent diameters, the larger bore being at the forward end and formed with a tapering seat. A port 1() opens through said seat and registers with an inletport 11 in the valve-h ook. The stem N may be made integral with the throttle-valve N, as shown in Fig. .1, or it may be separate therefrom, as shown in Fig. 3. In the latter esse the stem is formed with a shoulder 1 2, which revents entire withdrawal of the stem from t ic head. A spring 13 normally holds the throttle-valve to its seat, and when the stem N is not integral with the valve the siring holds the va ve in engagement with tlie stem, and when the latter is pushed forward by means of the grasping-handle the valve is held awav from its seat. A recess 14 is formed in the forward end of the throttlevalve, and the spring 13, seated in saidreeess and bearinur against a )lug or cover 15, which closes the l taining-head, normally retains the valve N, stem i", and grasping-humilla (l in a rearward position with relation to the head, as shown in Fig. 1. The stem N', throttlevalve N, and spring 125 are inserted into the bore of the head M fronggl'lie forward end, and

-said end of the bore is closed by the plug 15,

which lits tightly th rin, wherebysaid parts are held in assembled position and retained s1 antially the Forward ein of the bore of the reoi the valve shown in Fig. 2,7i

in the head. A assage 16 is formed in the handle 0, exten one arm and registering with a assage 17, extendin down into the forwardp end of the stem. e outer portion of the passage in the handle is screw-threaded or otherwise adapted for connection with a source of fluidressure sup ly. (Not shown.) A series of holes 18 are ormed through the wall of the stem at the forward end, through which the motive fluid will pass into the larger bore of the head when the stem is in a forward p0- sition. A port 1() and passage 19 leads from said larger bore in the head and extends down inside of the wall of the rhead and through the forward end and registers with an inlet passage 11 and port 20 in the valveblock I. When the grasping handle is ushed forward, the throttle-valve will also lie moved forward and the port 1() covered, thus leaving a free passage for the motive fluid from the passage 17 in the handle through the holes 18 in the stein and passage 19 in the head to the inlet-passage 11 and ort 20 in the valve-block.

The valve J consists of a tubular shell of different diameters provided with an annular groove 21, formed between the large and small diameters, said groove being always o en to the inletort 2() in whatever position t ie valve may e, and since the annular shoulder 22 on one side of the groove is of greater a'rea than the shoulder 23 on the other side of the groove the motive fluid always tends to press the valve in a forward direction. The valve is provided with an annular groove 24 at its large diameter, which is open to the interior by a series of holes 25. Said valve, as sliown in Fig. 2, is irovided with a small projecting end 126, whieli 'fits into a bore in the plate or head l'l, the end of said bore forming a sto for the forward movement of the valve. 'l here is a small hole 27 through the stein 2G, so that both ends of the valve are connected with the interior, and the motive fluid which is admitted to the forward end of the valve-chamber to move the valve rearwardly, as will be hereinafter described, acts ou the annular shoulder between the large diameter of the valve and the small projet-ting end. the large end and provide the same with a slight projertiou of small diameter, which permits the motive fluid to nel` against subwhole area of the. forward end will be unl prefer to close the valve at ing longitudinally through tig ol' the valve to shift the latter when the duid isA admitted thereto when the valve is held against the plate ll by the eonstaidiy-acting pressure ou the dill'erential surfaces of the annular groove 21, as shown in Fig. 1. The valves shown in Figs. 1 and 2 are substantiall)v the same, the only7 difference being that the valve shown in Fig. 1 has y solid projecting end that is shorter thanv e tubular end A passage 28 in the valve-block is provided with a port 29, opening into the valve-chamber. Said passage registers with a passage 30 in the plate H, which registers with a passage 31 in the wall of the cylinder, said passage 31 having a' port 32 openin into the rear end of the is ton-chamber. passa e 33 in the va veblock isprovided with t 1e ports.34 and 35, opening into the valve-chamber. Said passage 33 re isters with a passage 36 in the plate H, w ich registers with a passage`37 in the wall of the cylinder, havingaport 38 open ing into the forward end of the piston-chamher. When the valve J is in the forward position, as shown in Fi 1, the motive lluid will pass from the annu ar groove 21 through the port 29, passages 28 30 31, and port 32 to the rear end of the piston-chamber. The ex. haust from the forward end of the pistoneharnber will pass throu h the port 38, passages 37, 36, and 33, an the greater part` of the exhaust will pass through the port 35 in the valve-block, which is of reater capacity than the port 34, through w ich the motive fluid is supplied to the forward end ofthe piston-chamber, as will be hereinafter described. The plug 15 is rovided with a port 39 in alinement with t ebore 40 of the valve. Said port 39 is connected by a passage 41 in the plu and head with a channel 42 in the side of t e valve-block, which opens into an an-v.'

nular groove 43 in the outside of the valvehloek. The oove 43 is o pen to the'atrnosphere throug the ort 44 in the sleeve K, asl

shown in Fig. 2, w ereb the interior ofthe valve is always open to t e atmosphere,l The exhaust from ,the forwardend of the piston chamber that passes through the port 35 en` ters the groove 24 in the valve and asses to the interior` thereof through the cles 25. The exhaust that passes through the port 34 passes by the rear end of the valve and with the exhaust from the interior of the valve passes to the atmosphere through the port 39 1n the plug, passage'41, channel 42, groove!Y 43, and ort 44. en the valve is in its rearwar position, the port 34 will be open to the groove 21 inthe valve and the motive iluid will pass by the connecting-passa es before mentioned to the forward end of t e is ton-chamber to drive the piston rearwardly The exhaust from the rear end of the pistonchamb'er will pass through -the port 32,'passages 31, 30, and 28, and ort 29A to the groove 24 in the valve, whic registeljswith said port .2 9 when the valve is 1n its rearward osition, the exhaust passing through the ho es 25 to the interior of the valve and to the atmosphere by the same ports and passages as described in connection with the exhast from the forward end of the piston, since the interior of the valve is always open by means of said ports and passages to the atmos here. A The port 34 in the valve-block is ma e of sulcient capacity to drive the piston rearwardly at the required speed when the valve is in its rearward position and serves as an exhaust-port when the valve is in its forward position; but since it is desirable to limit the amount of motive fluid admitted to drive the piston rearwardly the port 35 is made of cons1derably greater capacity and rovides additional means for exhausting the uid from the forward side of the piston and 'also rovides additional means for quickly relieving the pressure from the forward end of the valve when the piston approaches the end of its rearward stroke, as will he hereinafter described. A passage 45 in the valve-block is provided with a port 46, which is always open to the roove 21 in the valve, as shown in Fig. 2. aid passage 45 re 'sters with a passage 47 in the plate H, w 'ch re xsters with a passage 48 in the wall fof the cy inder, having a port 49 opening into the piston-chamber. A passage 50 in the ,wall of the cylinder leads from the forward Yend of the valve-chamber through the late H to near the forward end of the piston-c amber and is rovided with the ports 5l 52, opening into the piston-chamber. An exhaust port 53 opens through the wall of the cylinder and jacket to the atmosphere. The piston is provided with an annular groove .'34 near its rear end, and when the piston is near the end of its forward stroke the groove 54 connects the live-fluid passage 48 with the passage 50, leading to the large area of the valve, and the 4motive fluid actingl on said large area of the valve overcomes t e constantly-acting pressure on the differentialressure surfaces of Vthe cove 21 to move t e valve to its rearwar position. The retaining-head M is provided with a small ort 55, connecting the passage 19 with the ore 'in the head forward of the front end ofthe throttle-valve, so that i when said valve is away from` its seat the Ino- .tive fluid will act against the forward end of,

said valve to balance the ressure of the fluid on the rear end 4of the' atter to allow the pring 13 to seat the valve. When the throti` connected passages, so that 1t 1s only necessa to overcome the spring-pressure to move sai valve forward. Although I have shown the throttle-valve seated by isprngpressure, it will be understood that the spring 1 3 may be `omitted and the valve be seated by the luidpressure. By omitting the port 55 and connecting the recess 14 Vof the yvalve with the `passage 17 in the stem the motive fluid will constantly act to Vpress the valve in a rearward direction; but since the throttle-valve must he of quite large diameter in the present instance in order to allow for a passage of sufoient capacity through the stem withhigh fluid-pressures it may require quite an effort on the part of the operator to start the valve from its seat; but after the valve is unseated IDO e-valve is seated, the pressure ontheffront 4end is relieved through the port -55 and the `the motive fluid that ma smaller diameter of the stri er in the bore of .bushing tion, there is it is practically balanced. The head M is provided with the stuffing-box P, which can e adjusted to provide for wear of the stem N' in the bore of the head, and thereby prevent the escape of the motive fluid between the stem and the bore ofthe head. The 'amnut Q serves to prevent the stufiing-box irom unscrewing and to hold the latter in adjusted osition on the head. The threaded sleeve serves to hold the plate H, valve-block I, and the retaining-head M in assembled position with relation to the cylinder. clamp L is provided with a bolt which passes freely through one lug and is in threaded engagement with the other lug. Said bolt is rovided with a jam-nut to revent unscrewl-ng of the bolt. The clamplhas a bore of dif- 'ferent diameters, one diameter being adapted to grip the clylinde'r and the other diameter to grip the s eeve to prevent the latter from turning with relation to the cylinder when in assembled position.

The forward cylinder-head C has a bore of different diameters, the bore of lar est' diameter having a bushing D fitting tig tly therein, saidbuslng having an openin 56 of noncircular cross-section to receive t e non-circular shank'of the worki tool.4 A striker E is movabl .mounted in iie bore of the head and provided Wit' a rearwardly-projecting stem extendin into the cylinder. The striker is provi ed with a series of longitudinal grooves 57, which are adapted to prevent leak past the the head from exerti a pressure on the annular shoulder 58 o the striker. The head is provided with a port 59, opening into the bore between the rear end of the D and the forward end of the striker. Thefiuid leaking past the stem of the striker will ass through the grooves 57 and out throug the port 59, thereby preventing an accumulation of pressure to act on the annular shoulder` 58 of the striker, which would tend to ush the striker forward, thus moving the tool)baclrward with relation to the workingtdol, so that `the latter would not be retained in its proper position with relation to the stroke o the piston. A s lit clamp F grips the head and cylinder an is provlded with a handle F for rotating the tool with relation to the grasping-handle and source of fluid-pressure su ply, therebyT rotating the working tool wi h relation to the work.

I desire to lay especial emphasis on the advantages of my novel form of throttle-valve when employed in an im act-f. `)ol which is rotated with relation to t e source of luidpressure supply. Since the valve is not in contact with its seat when the tool is in operaractically no wear on the seat of the valve, an if there should be any wear between the valve and its seat it is automatic- The splitber passes .hcreinbefore described.

ally taken up by the longitudinal movement of the valve with relation to the head by the pressure of the spring.

The operation is as follows: When the tool is pressed to the work by means ol the graspin -handle, the stem N7 pushes the throttleva ve from its seat and the motive fluid will pass through the passage 19 in the headand the passage 11 in the valve-block into the annular groove 21 in the valve, thence through the port. 46 and passages 45, 47, and .48 and port 49 into the roove 54 in the piston when the latter is in t e osition shown in Fig. 1. The port 52 being a so open to the groove in the piston when the latter is at or'ncarthe end of its forward stroke, the'motivc l luid will pass through the passage 504 to the forward end of the valve-chamber and acting on th(` large area of thc valve will overcome the constantly-acting pressure on the smaller arca and move the valve to its rearward position. The port 34 being open to the groove .21 in the valve, the motive fluid will pass through passages 33 36 37 to the forward end of the piston-chamber and drive the piston rearwardly. When the valve is in lts rearward position, the port 35 is open to the valve-chamber l'orward of the front end of the valve, as shown in Fig. 3, and when the piston on its rearward stroke uncovers the exhaust-port 53 the motive fluid that was actin on the large area of the valve to maintain le latter in position will pass through the port 35 and passages 33 36 37 to the forward end of the piston-chainber and escape to the atmosphere throughthe port 58, The cross-sectional area of the port 34 is small compared to the cross-sectional area of the port 35, passages 33 36 37, and port 53, so that although the port 53 is opened while the motive fluid-1s being supplied to the piston-chamber through thc port 34 thc pressure on the large area of the, valve is quickly reduced to allow the constantly-acting pressure on the valve to move the latter to its forward position. When the piston has moved a short distance on its rearward sirokc, it closes the port 52 and immediately opens the auxiliary port 51, whereby the motivo lluid that is moving the piston rearwardly will maintain a pressure on the large arca of tin` valve until the port 53 is opened by thc piston, and then the passage 50 nud the port 5i serve as additional means for conducting the fluid from the large area of thu valve to thc` piston-chamber, the latter being open to tlu atmosphere through said port 51%. The rxhaust from the roar end ol' the pistou-rhomthrough tlul passages l] ISU JH to the groove 24 of the valve and to the interior of the latter, which is always open to the atmosphere by nicans of the ports and passages When tlui vulve is moved to its forward position, as described, the passages '.28 3l) 31, leading to, tlw ron r of the piston chamber, will be open to tln` IOO ' blockfor contro oove 21 in thevalve and the motive fluid will be admitted in the rear of the 1piston to drive the latter forward. When t e piston moves forward a short distance, it closes the 54 exhaust-port 53, and the Huid in front of the piston then passes through the passages 37 36 33 to the ports 35 34, the greater part passing through the port 35 to the interior of the valve, and the other part passes through the 1o ort 34 past the end of the valve. The port 51 being open to the piston-chamber during the greater part of the forward stroke of the piston, there can be no accumulation of fluidpressure against the larger area of the valve until the port 51 is closed by the piston as it approaches the end of its stroke. Said port is closed by the forward end of the piston slightly before the port 52 is connected y the groove 54 in ,the piston with the live-fluid paszo sage 48, whereby the motive fluid admitted to the passage to shift the valve is prevented from escaping through the passage 37 to the exhaust.

I claim as my inventio11` 1. In a fluid-controlled impact-tool, a piston-chamber and piston, a tubular valve for controlling the movements of the piston',-

means controlled b said pistonfor actuating said valve, a valvelock or the valve having a bore of two diameters in alinement with the piston-chamberand a ort openjninto the innerend of the lar er meter oft e bore= a retaining-head for t e valve-block adapted to limit the travel of the valve in the direction of said head to prevent the'valve-closin said port, and a ort in the forward end of t e retainin -hea the va ve-block which is always open tothe interior of thevvalve'. j

2. i In a fluid-controlled impact-tool, a piston-chamber and piston, a valve-block ing a bore of two diameters in alinement with' the piston-chamberand ay port opening into the inner end of the lar er diameter of the bore, a tubular valve in t e valve-block' provided vvith opposing pressure-'sfaees of diflferent areas to which the motive iluidisadmitted to move the valve in oppositedirec-v end o theretaining-lea -iualinementwith the bore of the valve-block 'which isfalways' open to the interior of the valves i ing a. bore of two .diameters in 'elinement with ing at the rearendofsaidfblockjnd apoift openinginto `the inner end ofthe diameter of the bore, a -tubular valve inA c valvethe movements of the piston, means contro ed by the iston for acstuating said valve, arretaining'- ead for-the'.

in alinemont with the bore of.

- tions, a retaininghead for thevalve-bleek 3.- in a aula-@osseuse impara-toni stai. ton-chamber and piston, a valve-bloc -havthe piston-chamber, thesmaller diameter bevalve-block adapted to limit the travel of the valve in a rearward direction to prevent the valve closing the said port, and a port in the forward end of the retaining-head in alinement with the bore of the valve-block which is al- 7o ways open to the interior of the valve.

4. In a fluid-controlled impact-tool a piston-chamber and piston,a valve-bloc having a bore of two diameters in alinement with the piston-chamber, the smaller diameter. being at the rear end of-said block and a port opening into the inner end of the lar er diameter of the bore, a tubular valve in t e valvebiock for controlling the movements of the piston, having 'diameters corresponding to the bore of the valve-block and an annular grooverbetween the large-and small diameters, means controlled by the piston' for actuatingV said valve, e retainin -head for the valve-block adapted to limit t e travel of the valve in arearward direction whereby said port in the valve-block is always open to said annular oove in the valve, a oijt' in the forward endrof the retaining-hea in alinement with the bore of the valve-block which is al- ;ways open to the interior of the valve.

5. In a fluid-controlled impact-tool a piston-chamber and piston, a valve-bloc having a bore of two diameters in alineinent with the Eigen-chamber, a tubular valve for oonis i trol the movements of the piston, means contro ed by the piston for actuating the valve, said valve having an exterior annular groove open to theI interior of the valve, a port in said valve-block connected b a passage to one end of the piston-cham er and adapted to re 'sterwith said oove in the valve whenvt e latter is at t e end of its movement in one direction, a passage leading from the opposite end of the piston-chamber provided with two ports, one of-said ports opening into the smaller bore of the .valveb ook, the other of said ports opening into the larger bore of the block and adapted to register with said annular groove in the valve i 1o w en the latter is at the end of its movement in an o posite direction, a retaining-head for the-va ve-block having a port in alinement with the bore of said block whereby said lastyii'aentioned' port is alternately placed incomx15 'munication through said groove in the valve :with opposite ends` of thepiston-ciiamber.

= 6. In aliuid-cpntrolled impact-tool a 'piston-chamber and piston, a valve-bloc hav- Jing a bore of Vtwo diameters 1n aluieinent` with i :o

the,l laten-chamber,- a tubular `valve for con! ;trolng the movements of the piston, means eontre led by the "piston for actuating the valve, said valve having an exterior annular f `groove open to the interior of the valve, a ia --port said valve-block connected b a palss e to onefend of the piston-cham er and a apted to register with 'iid groove in the valve when the latter is i.y ts rearward position, a passage leadingr fri` 1. the opposite end 13o of the piston-'chamber provided with two ports, one of said ports o ening into the smaller bore of the valvelock, the other port opening into the larger bore and adapt- .ed to register with said -groove in the va when .the latter is in its forward position, a retaining-head for the valve-block having a port in alinement with the bore of said block whereby the opposite ends of the pistonchamber are alternately placed in communication through said groove` in the valve with said last-mentioned port.

7. In a fluid-controlled impact-tool, a piston-chamber and piston, a valve-block having a bore of two diameters in alinement with the iston-chamber, a tubular valve for control in the movements of the piston, means contro led by the piston for actuating the valve, said valve having an exterior annular groove open to the interior f the valve, a port in said valve-block connected b a passage to one end of the piston-cham er and adapted to register with said groove in the valve when the latter is in its rearward position, a passage leading from the o posite end of the piston-chamber provide with two ports, one of 'said ports o ening into 4the smaller bore of the valvelock; the other port pcning into the larger bore and ada ted to register with said groove in the val)ve when the latter is in its forward osition, and

open to the bore of the valveook forward o said valve when the latter isin its rearward osition. f

8. n a fluid-controlled impact-tool, a piston-chamber and piston,la valve-block having a bore of two diameters in alinement with the iston-chamber, a tubular valve for controlling the movements of the piston having opposin pressure-surfaces of different areas.

to whici the motive fluid is admitted to move the valve in opposite directions, means controlled by the iston for actuating the valve, said valve belng pro'vided with an exterior annular roove located between the large and smal diameters, a port in said.

valve-block connected by a passage to one end of the piston-chamber and Aadapted to re istcr` with said annular grooveV in the va ve when the latter s at the end of its movement in one direction, a passage leading from the opposite end of the piston-chamber provided with two ports opening into the valve-block, one of said last-mentioned ports being adapted to re ister with said annular groove in the valve w en the latter is at the end of its movement in. an opposite direction and the other of said last-mentioned ports being open to the larcrer area of the valve when the latter is in said fast-mentioned osition.

9. In a fluid-controlle impact-tool, a pisten-chamber and piston, avalve-block having a bore of two (hamsters in alinement with the piston-chamber, a tubular valve for controlling the movements of the piston having opposin pressure-surfaces of different areas to whic the motive iiuid is admitted 'to move the valve in opposite directions, means controlled by the piston for actuating the valve, a passage leading from one end of the piston-chamber provided with two ports controlled by said valve, one of said ports opening into the smaller and the other opening into the lar er bore of said valve-block, the latter port eing adapted to admit the motive fluid from said passage to the larger area of thev valve when it is in one position said port being opened by the valve to exhaust the motive fluid from said passage when said valve is in an opposite osition.

10. In a fluid-contro led impact-tool, a piston-chamber and piston, a valve-block having a bore of two diameters in alinement with the piston-chamber, a tubular valve for controlling the movements of the piston having opposin pressure-surfaces of different areas to whic the motive fluid is admitted to move the valve in opposite directions, means controlled bythe piston for actuating the valve, a passage leading from one end of the piston-chamber provided with one port opening into the smaller and another port openin to the larger bore of the said valve-block, said ports bein controlled by the valve; the firstmentione port being opened to admit motive fluid through the said passage to the said end of the piston-chamber, and the other port being opened to admit the motive fluid from the said passage to the larger area of the valve when the valve is at one end of its stroke. A l

ll. In a fluid-controlled impact-tool, a piston-chamber and piston, an valve-block havin a valve-chamber of two diameters in alinement with the piston-chamber, a tubular valve located therein provided with opposing pressure-surfaces of different areas to which the 'motive fluid is admitted to move travel of the valve, said head being provided with a port in alinement with the valve and always open to the interior of the latter.

12. In a Huid-controlled im act-tool, a piston-chamber and piston, a va ve for controlling the movements of the piston provided with opposing pressure-surfaces of different areas to which the motive iuid is'admitted to ,shift the valve,' and against the smaller of which areas the motivefluid constantly actsV t0 pressfthe valve in one direction, a passa e controlled by the piston and opened by t e latter when yit approaches one end of its stroke to admit motive fluid to the larger" `lin the movements of the piston provided wit opposin rassure-surfaces of different areas to whic t e motive lluid is admitted to shift the valve, and against the smaller of which areas 'the motive lluid constantly acts to press the valve in one direction, a passa e controlled by the piston and opened byt e latter when 1t approaches the forward end of its stroke to admit motive fluid to the lar er pressure-surface of the valve to shift t e valve, said passage bein opened by the iston on its rearward stroe to admitan a ditional amount of motive lluid to said pressure-surface of the-valve to retain the valve in said position until the piston a preaches the end of said last-mentioned stx-olie.

14. In a {luid-controlled im act-tool,a piston-chamber and piston, a va ve for controllin the movements of the piston providedwit opposingi pressure-surfaces of different areas to whic the motive fluid is admitted to move the valve in op osite directions, and against the smaller of w ichv areas the motive fluid constantly acts to press the valve ferward, a passage controlled and opened by the pistonr when it approaches one end of its stroke to admit motive fluid `to the lar er pressure area of the valve to move the va ve rearward, said passage being opened by the piston on its opposite stroke to admit an ad-4 ditional amount of fluid to said larger area of` the valve tovretain the valve in position until the piston approaches the end of said lastmentioned stroke. a v

l5. In a fluid-controlled im ton-chamber and piston, a v ling the movements of the with opposing act-tool, a pisve for controlpiston provided ressure-surfaces of different areas to which t e motive iluid is admitted tomove the valve in opposite directions, and against the smaller of which areas the motive fluid constantly acts to press the valve in one direction, a passage by the iston when it a proaches one end of to admit motive fluid to the said passage being opened by the piston on its opposite stroke to admit an additional amount of motive fluid to the larger area of the valve, and an exhaust-port opened lby the piston when it approachestheend' of said astmentioned stroke te 'exhaust the motive fluid from said larger area of the valve.A

16. In a fluid-controlled im act-tool, a piston-chamber and piston, a valve for control- 1m29.` the movements 'of the piston provided controlled and opened' larger' pressurearea of the valve to move the valve,

Vmove the valve inl opposite directions and against the smaller of which the motive fluid constantly acts to press the valve forward, a passage leadin' from the larger area of the valve tothe lston-chamher controlled by the piston an opened by the latter near the end of its forward stro e to admit motive fluid to the larger area of the valve to move the valve'rearward said passage being opened by the piston on its rearward stroke to admit an additional amount of fluid to the l er areay of the valve, an exhaust-port opened y the piston near the end of its rearward stroke to reduce the pressure on the larger-area of the valve to allow the constantly-acting pressure on' the smaller area oi the valve to move the valve forward, said valve when moved forward opening a passage leading from the forward end of the piston-chamber to allow the motive iluid te escape from said end of the laten-chamber and from the larger area of t e valve; q

17. In a {luid-'controlled im act-tool, a piston-chamber and piston, a va ve for controllin the movements of the piston provided wii opposing rassure-surfaces of different areas to which t move the valve in opposite'directions,V means controlled by the piston for actuating said valve, passages leading from said valve to opposite ends of the piston-chamber to alternatel admit and exhaust the motive fluid to and om said ends of the iston-chamber, a passage leading from the arger area of they 'valve to the piston-chamber, said passage being" always open to one end of the pistonchamber exce t when the piston is near one end of. its strol-ie whereby the motive fluid is alternately admitted to and exhausted from the larger area of the valve during the intermediate travel of the rections. Y

18. Ina fluid-controlled im act-tool, a piston-chamber and piston, a valve for controllin the movements of the piston provided wit opposing plressure-surfaces of different areas to which t e motive lluid is admitted to move the valve in opposite directions, a pa'ssage leading to one end oftle piston-chamber and controlled by said valve to alternately admit and exhaust motive fluid to and from said end of the iston-chamber, a passage leading from the erger area of the valve to said end of the piston-chamber whereb motive fluid is admitted to' and euchaustedy from the large area of the valve through the piston-chamber, said last-mentioned passage being closed to the piston-chamber by piston when the piston is near saidv end of tf e piston-chamber, a liver-fluid essa-ge leading om the source of su ply to tllie piston-cillin:- ber and opened by tlxie piston to said passage leading to the larger area ofthe valve to slnf t piston in opposite die motive fluid is admitted to IOC lIO

the valve when the piston is at said end of the piston-chamber.

19A Ina fluid-controlled impact-tool, a piston-chamber and piston, a valve-block having a valve therein for controlling the movements of the piston, a retaining-head for the valve-block having a bore of dlfferent diameters in alinement with the piston-chamber, the larger diameter being at the forward end of the head and forming an internal shoulder near said forward end, a throttle-valvo loeated in the larger bore of the head and provided with a rearwar(ily-projecting stein oi' smaller diameter, said throttle-valve being adapted to be seated against said shoulder when in a rearward position and means for normally holding said throttle-valve in seated position.

20.' In a fluid-controlled im pact-tool, a piston-chamber and piston, a valve-block having a valve therein for controlling the movements of the piston, a retaining-head for the valve-block having a bore of different diameters in alinement with the piston-chamber, the larger diameter being at the forward end of the head and forming an internal shoulder near said forward end, a throttle-valve for controlling the initial admission of motive Huid. to the tool, said throttle-valve bein located in the larger bore of the head and "nted to be seated against said shoulder when in a rearward position, means for normally holding the throttle-valve in seated position, a stem located in the smaller bore of the head and enga in said throttle-valve, a graspinghandgie For holding the tool to the workl and adapted to hold said throttle-valve in an unseated position when the tool is held to the work.

21. In a Huid-controlled impact-tool, a piston-chamber and piston, a valve-block having a valve therein for controlling the movements of the piston, a retaining-head for the valve-block having a bore of different diameters in alinement with the piston-chamber, the larger diameter being at the forward end the head and forming an internal shoulder near said vforward end, a throttle-valve for controlling the initial admission ol.' motive Huid to the tool, said throttle-valve being located in the larger bore of the head and adapted to be seated against said shoulder when in a rearward posltion, means for normally holding the throttle-valve in seated position, a stem located in the smaller bore of said head, means to retain said stern in the head, a grasping-handle secured to said stem and adapted 'for holding the tool to the work, said grasping-handle and stem being adapted to old said throttle-valve in an unseated position when the tool is held to'tie work.

22. In a fluid-controlled impact-tool, a piston-chamber and piston, a valve-block having a valve therein for controlling the movements of the piston, a retaining-head for the valve-block having a bore of diierent diam eters in alinement with the piston-chamber, the larger diameter being at the forward end of the head and forming an internal shoulder near said forward end, a throttle-valve for controlling the initial admission of motive fluid to the tool, said throttle-valve being located in the larger bore of the head and adapted to be seated against said shoulder when in a rearward position, means for normally holdin the throttle-valve in seated position, said t `rottle-valve being provided with a rearwardly-projeeting stem of smaller diameter corresponding to the bore at the rear end of said head and means for closing the forward end ol the larger bore after the throttle-valve and stem are placed in position therein.

23. vln a iluid-eontrolled impact-tool, a piston-chamber and piston, a valve-block having a valve therein for controlling the movements of the piston, a retaining-head for the valve-block having a bore oln different diameters in alinement with the piston-chamber, the smaller diameter being at the rear end of the }1ead,said head having an internal shoulder nearthe forward end, a throttle-valve pro: vided with a rearwardly-projecting stem of snialler-dianieter corresponding to the bore at the rear end of the head said throttle-valve being adapted to be seated against said shoulder when in a rearward position, means for normally holding the throttle-valve in seated position, a grasping-handle secured to the stern for holding the tool to the work, said handle .--md stem being adapted tohold. said throttle-valve in an unseated position when the tool is pressed to the work.

24. 1n a fluid-Controlled impact-tool, a cylinder and piston, a valve-block having a controlling-valve therein,,a retaining-head for the valve-block Ihaving a longitudinal bore of different diameters, the smaller diameter being at the rear end of the head, a throttle-valve located in the larger bore and provided with a rearwardly-projeeting stern of smaller diameter corresponding to the bore in the head and rotatably mounted therein, means for holding said cylinder, valve-block and retaining-head in assembled position, and means whereby said cylinder may be rotatedwith relation to said stem and throttle-valve.

25. In a Huid-controlled impact-tool, a cylinder and piston, a valve-block having a controlling-valve thereini a retaining-head for the valve-block having a longitudinal bore of different diameters, the smaller diameter being at the rear end of the head, a throttle-valve located in the larger bore and provided with a rearwardly-projecting stem of smaller diameter, the throttle-valve being adapted to be seated in the head when in a `rearward position, said throttle-valve and stem being longitudinally and rotatably IOO ' adapted to ho d t e throttle-valve in an iin-- so with relation to said stem and throttle-valve.

4l'arger'bore of the head and provided with a V Work.

mounted in the bore of the head, means for holding said cylinder, valve-block and retaining-head in assembled position, and means whereby said .cylinder-may be rotated 26. In a fluid-controlled impact-tool, a eylinder and piston, a'valve-hlook having a eontrollin -valve therein, a retaining-head for the va ve-block having a lon itudinal bore of different diameters, the sma ler diameter being at the rear end ofthe head, a throttlevaive vlocated in the larger bore and provided with a rearwardly-projecting stem of smaller diameter, the throttle-valve being adapted to be seated in the head when in a rearward osition, said throttle-valve and stem Abeing ongitndinally and rotatablymounted in the bore of the head, a graspin -handle seeure-d to said stem and adapted for hoiding the tool to the work, said graspinghandle and stem being ada ted to hold the throttlevalve inan unseate y position when the tool is pressed to the Work, means for holding'` said cylinder, valve-block and retaining-head in assembled position and means Whereby'said cylinder may be rotated with relation to said grasping-handle and throttle-valve.

27. In a fluid-controlled impact-tool, a piston-chamber and piston, a valve-block having a valve therein for controlling the movements of the piston, a retaining-head for the valve-block having a bore of dii'erent diameters in alinement with the piston-chamber, the ler ervdiameter being at the forward end of the lead, a throttle-valve located in the rearwardly-pro'eating stem having a passage therein through which the motive .fluid is sipplied tothe tool, said throttle-valve being, a apted to be seated in thevhead when in a rearward losition, means for normally holdi-n'g the tliiottle-valve in Aseated position, a gra-spin -handle secured to said stern and adaptenI for holding the tool to the work, a passage in said handle communicatin with said passage in the stemand adapte to be connected to a source of vfluidressure supply, said gras in -handle an stem being i seated position when the tool is held to the 2S. In a fluid-controlled im act-tool, a o vlinder and piston, a valve-bloc having a controllEnV-valve therein, a retaining-head for the va ve-block having a lon'itudinal bore of flill'crent diameters, the smaller diameter being at therear end of the head, a throttlevalve located in the larger bore and rovided with a rearwardly-projeating einem o smaller diameter oorrespondin1r to the boreat the rear of the head am rotatably mounted therein, a passage in said stem through which the motive fluid is supplied to the tool, a grasping-handle secured to said stem having a passage communicating with said passage in the stem and adapted to be connected to a source of fluid-pressure supply, means `01' holding said cylinder, valve-block and retaininlg-head in assembled position, and means W ereby said cylinder may be rotated with relation to said grasping-handle and source of fluid-pressure supply.

29. In a Huid-controlled im act-tool, a piston-chamber and piston, a va ve for controlling the movements of said piston, means controlled by said iston for actuating said valve, a valve-bloc havin sport t erein controlled by said valve an connected by a passage to one end of the piston-chamber to admit and exhaust the motive fluid to and from one side of the piston, a passage leading from the o posite end of the piston-,chamber and provi ed with two ports opening into the valve-block, one of said ports being controlled by said ,valve to admit and exhaust the motivev fluid to and from said last-mentioned end of the iston-chamber and the other ofsaid ports eing controlled by said valve to provide additional means for eX- hausting the fluid from said end of the piston-chamber. i

30. In a huid-controlled im act-tool, a piston-chamber and piston, a va ve for controlling the movements of said piston, means controlled by said iiston for actnatin said valve, a valve-bloei( havin ports an( passages in proximity to the orvvard and roar ends respectively and connected with opposite ends of the piston-chamber and eon-l trolled by said valve to alternatelyr admit and exhaust the motive [luid to and lirom the respective ends of the pistonchamber, said valve-block being provided with an auxiliary port which is controlled by said valve to provide additional means for exhausting the fluid from one end of the piston-chamber.

3i. In a {luid-controlled im act-tool, a piston-chamber and piston, e va ve for controllig the movements of said istomineans controlled by said piston or actuating said valve, a 'valve-block hnving ports and passages inV proximity to the forward and rear ends respectively and connected with opposite ends of the pistonchamber and controlled by said valve to alternntelv admit and l 'iary port being of greater mi mcity than the port through which the motive -fluid is supplied to said passa re leading to said end of the piston-cham or, whereby additional means of greater ca aeity is provided for exhausting the fluid `the piston-chamber.

32. In aiiuid-controlled im aet-tool,aJ piston-chamber and piston, a va ve for controlling the movements of said piston, meansA om said forward end Vol controlled by said piston for actuating said valve, a valve-block having a port connected with a passage leading to, the rear end of the piston-cham er and a )ort connected with a passage leading to the orward end of' the piston-chamberl said ports being controlled by said valve to alternately admit and exhaust the motive fluid to and from 'the respective ends of the piston-chamber, an auxiliary port connected with the passage leading to said forward end of the piston chamber and opened by said valve when the latter is moved in one direction to allow part of the fluid from the forward end of the pistonchamber to exhaust through said auxiliary porta' 33. ln a fluid-controlled im pact-tool, a piston-chamber and piston, a valve for controlliner the movements of said piston, means contrdlled by said piston for actuating said valve, a valve-block havimr a port connected with a passage leading to t ie rear end of the pistonchamber and a port connected with a passage leading to the forward end of the pistonchamber, said ports being controlled by said valve to alternately admit and exhaust the motive fluid to and from the respective ends of the piston-chamber, an auxiliary port connected with the passage leading to said forward end. of the piston-chamber and opened b said valve when the latter is moved in one direction to admit an additional supply of air to the forward end of said valve and when moved in the opposite direction to allow part of the fluid from the forward end of the valvechamber to exhaust through said auxiliary 34. In a fluid-controlled impact-tool, a piston-chamber and piston, a valve for controlling the movements of the piston'consisting of a tubular shell having opposing pressuresurfaces of different areas to which the motive fluid is admitted to move the valve in opposite directions, a valve block having ports and passages connected respectively with opposite ends of the piston-clmniber and controlled by said valve to alternately admit and exhaust the motive fluid to and from the opposite ends of the piston, an auxiliary port connected with one of said passages and con-4 trolled by said valve to provide additional means for exhausting the fluid from one end of the piston-chamber.

35. In a fluid-controlled impact-tool, a piston-chamber and piston, and source of fluidsup ly, a valve for controlling the movements of tile piston, said valve bein rovided with opposing ressure-surfaces o different areas to which t 1e motive fluid is admitted to move the valve in opposite directions, an exhaustport opened by the piston near the end of its .rearward stroke to exhaust the Huid from the largest area of the valve, a live-air passage leading directly from the source of supply to the piston-chamber, a passage leading from the piston-chamber to said larger area of the valve, said last-mentioned passage having two ports opening into the piston-chamber, one of said ports being connected to said liveair passage by a groove in the piston when the latter is near the end of its forward stroke7 the other of said ports being adapted by the shifting of the valve to admit an additional amount of fluid to the larger area of the valve on the rearward stroke of the piston.

36. In a fluid-controlled impact-tool, a piston-chamber and piston, and source of fluidsupply7 a valve for controlling the movements of the piston, said valve bein(y provided with opposing pressure-surfaces o` different areas towhich the motive fluid is admitted lto move the valve in opposite directions, an exhaustport opened by the piston near the end of its rearward stroke to exhaust the fluid from the largest area of the valve, a live-air passage leading directly from the source of supply to the piston-chamber, a passage leading from the piston-chamber to said larger area of the valve, said last-mentioned passage having two ports openiiw into the piston-chamber, one of said ports tbeing always closed by the piston except when the latter is near the end of its forward stroke, the other of said ports being always open to the piston-chamber except when the piston is near the end of its forward stroke and is adapted by the shifting of the valve to alternately admit and exhaust the motive fluid to and from the larger area of the valve.

37 ln a fluid-controlled impact-tool, a piston-chamber and piston, and source of Huidsupply, a valve for controlling the movements of the piston, said valve bein provided with opposing pressure-surfaces o different areas to which the motive fluid is admitted to move the valve in opposite directions, an exhaustport opened by the piston near the end of its rearward stroke to exhaust the fluid from the largest area of the valve, a live-air passage leading directly from the source of supply to the piston-chamber, a passage leading from the piston-chamber to said larger area of the valve, said last-mentioned passage having two ports opening into the piston-chamber, one of said ports being controlled by the piston and opened by the latter to admit motive fluid to the larger area ofthe valve and the other of said ports being controlled by the piston to alternately admit the motive fluid to and exhaust it from the larger area of the valve durin the travel of the piston.

3S. In a uid-controlled impact-tool, a piston-chamber and piston, a valve-block havinga valve-chamber of difl'erent diameters, a tu ular valve for controlling the movements of the piston, means controiled by the piston for actuating the valve, said valve being provided With a series of holes or ports opening into the interior of the valve, a port in said valve-block connected by a passage to one eiaeei end of Athe 7 iston-chamber and adapted to register Wit one or more of saidholes or ports in the valve when the latter is at the end of its movement in one direction, a paslother of said orts opening into the larger diameter of t e valve-chamber forward of said valve when the iatter is at the end of its rearward movement.

39. In a fisici-controlled'impact-tool, a pis'- ton-chamber and piston a valve-block havina valve-chamber of different diameters, a tu uar valve for contro the movements of the piston, means contro ed by the piston or'actuating the valve, said valve havin 'an 'exterior annular groove, a port in said va ve-V block connected by a passage to one end of the said groove in the valve when the atter is at the end of its movement in one direction, a passage leading from the opposite end of the piston-chamber provided with ltwo ports, one of said last-mentioned ports opening into the smaller diameter of the valve-chamber, the other of said orts being open to the lar er diameter of the valve-chamber forwar of said valve when the latter is in its rearward position. Y

40. In a duid-controlled impact-tool a piston-chamber and piston, a valve-bloeit having a vaive-cliamber and a valve therein for eontroliin the movements of the iston a retainingead having a bore of di erentdiameters in alinement with the valve-chamber and separated from the latter by a reiiicrrvr-V abie partition, a throttle-valvelocated in the larger bore of the retaining-head and prof. vi edwith a rearward] -projecting stem of diameter to fitthe sma er bore of the head, said throttle-valve being adapted to be seated in the head when in rearward position an means for normally holding said throttlevalve in seated position. f

41. In a {inici-controlled impact-tool a piston-chamber and piston a valve-bloei: hav- A ing a' valve-chamber and a valvethsrein for SAO controlling the movement of the iston, g. retaining-head having a bore of di erent diameters in alinement with the .valvefcliamber Aval and separated from the latter by a remova throttle-'valve located in the lar er bore ofthe retaining-head and adapted to ge seated therein when in a rearward osition, means for normally holding the t ottle-valve in seated position, ya stemlocated the smaiier bore of the head and eiiigifngl e or said throttle-valve, a graspmhan holding the tool to the work an adapted-to hold said throttle-valve in an unseated posil tion when the tool is held to the work.

42. In a fluid-controlled impact-tool a piston-chamber and piston, a valve-bloei; havpiston-chamber and adapted to register with4 pressure, a valve or controlling .i motive uid to' the lar r pressure-s Vton#eiiaiiiber and i ments ofthe piston, vided with opposing preaces of different areas to which YAin Aa forward direction,

said piston for actuetinghsaid valve, an auxby t er ltter on its rearw ing 4a valve-chamber and a valve therein for controllingl the movements of the iston, a retainingead having a bore of di erent diameters in alinement with the valve-chamher-, a7 throttle-valve iocated in the larger bore of the retaining-head and provided with a rearwardly-projecting stem of a diameter corresponding to the smallerbore of the head, a removable partition which separates the valve-chamber from said bore in the head, a

port in the forward `side of said partition in alinement with the valve'- chamber, said l throttle-valve being adapted to be seated in said -head when in a rearward position, a gras ing-handle for holding the tool' to the wor and ada ted to hold said throttle-valve in an unseate position when the tool is held to the work.

43. In a {luid-controlled impact-tool, a p isiston, a source of Huidthe move-v ments of the piston, said valve being provided with opposi prossime-surfaces o dilerent areas'to whic the motive fluid is admitted to move the valve in opposite directions and to the smaller of which areas the motive fluid is constantly admitted to press the valve in one direction, means controlled by said pia ton for actuating said valve, an auxiliary port controlled by the piston and opened by the latter to admit an additional amount of ace of the valve to retain the atter in position'when the piston is on its rearward stroke.

44. Ina Huid-controlled impact-tool, a pia iston, a source of uidor eontroiing the move' said valve being proton-chamber and pressure, a valveA the motive is adinitted to move the valve in o te direc- Pf which areas tions, and against the smaller o uid the motive constantly acts to presi the d valve in one direction, imeans controlled said piston for actuating said valve, uxiirt. controlled by the piston, and ciosed stroke,

ana

irr by t e latter when at one 4end of its said auxiliary ort wheii-uncovered by the piston s. apted b the shift of the valve to alternately a mit motive uid to and exhaust it from the larger area of the ve. 45. In a {luid-controlled impact-tool, a piston-chamber and iston, asource of uidpressurea vaive or controll" the movements of the piston, said valve bem provided with opposing rfaces o dierent rassure-su areasto which t e motiveliiid is admitted to Vmove the vave in vopposite directions, and

a einst the smaller ,which areas thermotive Huid constantly acts to press the valve ilia portcoiitrolledb e istonandopened stroke to admit IOC ins

m'eans controlled by. i

an additional amount of motive fluid to the larger pressure-surface of the valve to retain the latter in a rearward position.

46. ln a fluid-controlled iinpact-to0l,a piston-chamber and iston, a source of fluidpressure, a valve 'or controlling the movements of the piston, said valve being provided with opposing pressure-surfaces of different areas to which the motive fluid is admitted to move the valve in opposite directions, means controlled by said piston for actuating said valve, an auxiliary port con,- trolled by the piston and closed by the latter when at one end of its stroke, said auxiliary port being open to the piston-chamber to exiaust the motive fluid lroin the larger pressure-surface of the valve when the iston is on its forward stroke and adaptedP by the shifting of said valve to admit an additional amount of motive Huid to said larger pressure-surface when the piston is on its rearward stroke.

" 47. V[n a fluid-controlled impact-tool, a piston-chamber and iston a source of fluid- 7 pressure, a valve or controlling the Inoveinents of the piston, said valve being provided with opposing pressure-surfaces of different areas to which the motive fluid is admitted to move the valve in opposite directions, and a ainst the smaller of which areas the motive uid constantly acts to press they valve in one direction, means controlled by said piston for actuating said valve, an auX- iliai'y port controlled by the piston and opened by the latter, after the movement of the valve has been effected by the piston, to admit an additional amount of motive fluid to the larger pressure-surface of the valve to retain the latter in position.

48. In a fluid-controlled impact-tool, acylinder, a valve-block, aretaining-head, means for holding said cylinder valve-block and retaining-head in assemb ed position, a controlling-valve in said valve-bloek, said retaining-head having a longitudinal bore of different diameters, the smaller bore being at the rearward end of the head, a throttlevalve rovided with a rearwardlyrejecting stem aving a diameter corres on ing to the bore of the head, said thrott e-valve being adapted to be seated in the head when in a rearward osition, means for normally holding said tirottle-valve in seated position, a gras ing-handle adapted for holding the tool to t ie work, said grasping-handle and stem being adapted for holding said throttle-valve in an unseated position when the tool is pressed to the work.

4). In a fluid-controlled impact-tool, acylinder, a valve-block, a retaining-head., means .for `holding said cylinder, valve-block and retaining-head in assembled position, a controlling-valve in said valve-block, saidretaining-head having a longitudinal bore of dilereiit diameters, the smaller bore being at the rearward end of the head, a throttlevalve provided with a rearwardlyrejecting stein having a diameter corres )ending to the bore of the head, said thrott e-valve being adapted to be seated in the head when in a rearward position, means for closing the for ward end ol said bore after the throttle-valve and stem are placed in position therein, a passage in said retaining-head for conducting the motive fluid from the throttle-valve to a )ort in the valve-block, an auxiliary passage eading from said first-iiientioned passage to said bore iii the head forward of the end of said throttle-valve.

50. ln an impact-tool, a cylinder provided with screw-threads, a threaded member or sleeve adapted to engage said cylinder, a valve-block contained in said sleeve, a retaining-head for the valve-block having a-v flange engaged b f said sleeve, a split clamp having a bore of r iflerent diameters, one bore adapted to engage said sleeve and the other to engage the cylinder, said clamp being provided with projecting lugs, a threaded bolt engaging said lugs and having a jam-nut thereon.

51. ln an impact-tool, a cylinder, n ineinber or sleeve in threaded engagement with said cylinder, a valve-block contained in said sleeve, a controllingvalve in said valveblock, a retaining-head for said valve-block, a split clamp havin r a bore of different diameters and provide with projecting lugs, a threaded bolt engaging said lugs, one part of said clamp being adapted to grip the cylinder and the other part to grip the sleeve, said sleeve having a flange at its rear end adapted to engage said retaining-head to hold the latter in position.

52. ln an impact-tool, cylinder, a meinber or sleeve iii threaded engagement with said cylinder, a valve-block contained iii said sleeve, acontrolling-valve in said valve-block, a retaining-head for said valve-block, a plate located between said valve-block and cylinder, a split clamp heaving a bore of diil'erent diameters and adapted to grip said sleeve and cylinder, said sleevt` being provided with an internal annular flange at its rear end ada ted to engage said retaining-head to hold)the latter iii position.

53; In an inward-tool. a cylinder provided with a forward head having a loiigitudinal bore of different diameters. a striker operating in the bore and haring n stein of smaller diameter projecting rearwardly into the cylinder, a bushing ilting into said bore to prevent displacement of the striker and having an opening to reer-ive the shank of the working tool, said striker having a .series of longitudinal grooves in its largest diametr.

54. ln an iin inet-lool, a cylinder provided with a forwardhead having a longitudinal bore of diflerent diameters, n striker operating in the bore and haring a stein ol" smaller IIO 55. In Minid-controlled impact-tool a pgi ton-chamber and piston, a tubular vaive for controlling the movements of the piston, means controlled by said iston for actuating said valve, a valve-bloc having a valvechamber of different diameters and a ort openinginto said valve-chamber, a retaininghead for the valve-block having a bore of different diameters in alinement with the valv'echamber and separated from the latter by a artition, a throttle-valve located in the arger bore of said head and provided with a rearwardly-projectin stem of a diameter to fit the smaller bore cfg the head, said partition being adapted to limit the travel ofsaid valve to prevent closing said port in the valve-block.

56. In a Huid-controlled im act-tool a pistn-chamber and piston, a tu ular valve for controlling the movements of the piston, means controlled by said piston for actuating said valve, a valve-block having a valvechamber of different diameters and a port opening into said valve-chamber, retainin head for the valve-block having a bore of diferent diameters in alinernent'with the valvechamber and separated from the latter by a `partition, a throttle-valve located in the arger bore of said head and provided with a rearwardly-prolectin' stem of a diameter to fit the smaller bore 'o the head, said partition being adapted to limit the travel of said valve to prevent closing said port in the valvechamber which is l ton for actuating `means controlled by said iston for actuating said valve, a 'valve-bloc having a valve'- charnber of different diameters and a port opening into said valve-chamber, a retaininghead for the valve-block adapted to limit the travel of the `valve to prevent closin said port, and a `ort in the forward side of t e retaining-hea in alnement with the valvealways open to the interior of the valve.

58. In a Huid-controlled impact-tool, a piston-chamber and piston, a valve-block hav- Ving a valve-chamber of di'erent diameters,

a valvefor controlling the movements of the -ston having opposing pressure-surfaces of :lier-ent areas, means controlled by the pisin from one en of the piston-cham er prov1 ed with two ports, one of` said ports opening into the smaller and the other open-v lng into the larger diameter of the valvechamber, the latter ort bein adapted to admit the motive lui from sai assage to the larger area of the valve Whni e latter is in one position; said ortbeinglopened by the valve to exhaust t e motiveuid-from said passage when the valve is in aai-opposite position. v j

In testgilfnony .whereof I have affixed 'my signature 1n presence of two Witnesses.

GEORGE L. Banana. i

Witnesses:

WILLIAM A. COPELAND, ROBERT WALLACE.

the valve, a passa e lead- 

